First lady Michelle Obama on Tuesday said efforts in Congress to scale back school nutrition standards are “unacceptable to me not just as first lady but also as a mother.”

Obama made the comments at a roundtable she held with school food officials from Los Angeles; New York City; Burke County, Ga.; Norfolk, Va.; and Montgomery County, Md. Also attending was Shirly Watkins Bowden, former Agriculture Department Under Secretary for Food, Nutrition and Consumer Services and past president of the School Nutrition Association.

"The stakes just couldn't be higher on this issue," the first lady said, “because one in three children in this country are still overweight or obese, and one in three are on track to develop diabetes in their lifetimes.”

"Now is not the time to roll back everything we have worked for."

The new lunch standards were developed by experts at the Institute of Medicine.

The School Nutrition Association and some House Republicans are fighting to change the regulations. The SNA originally supported them as part of the 2010 Healthy Hunger-Free Kids Act.

The organization didn’t have a representative at the White House meeting. It said in a statement on Tuesday that the regulations were “overly prescriptive” and that fewer students were eating lunches. A survey by the organization found that in 2012-13, 47 percent of school meal programs said their revenue declined.

Obama, however, said that the number of students eating school lunches has increased in many school districts, and “more importantly, parents across the country finally have some peace of mind about what their kids are eating during the school day.”

The regulations require schools to offer more fruits and vegetables, whole wheat products and low-sodium foods. The guidelines have been phased in over the past two years.

Many Republicans in the House of Representatives argue that the school lunch program is too costly and will get more expensive with the new federal guidelines.

Republican Rep. Robert Aderholt of Alabama, the chairman of the House Agriculture Appropriations Subcommittee, recently said it’s time “to hit the pause button.” Last week, his panel approved a bill that would let districts get waivers to opt out of the healthier school lunch guidelines if they’re struggling financially to meet them. (More on the story here.)

Obama said she believed that nutrition experts should set standards, not Congress.

She asked the nutrition directors how it happened that there was opposition to the nutrition changes she championed.

Donna Martin, director of the school nutrition program for the Burke County Board of Education in Georgia, said students in her district eat lots of salads now, and two favorites are kiwi and cucumber slices with homemade low-fat ranch dressing.

“Our kids are worth it, y’all, do not let us go backwards,” she said.

“In the South, do you not think that taking fried chicken off the menu was dangerous? It was,” Martin added. “But we have an herb-baked chicken that our children love. We bake our French fries and we have whole grain, locally grown grits we do for breakfast that are awesome.”